1. Field of the Invention
This invention relates to transparent soap bars and liquids and methods for production thereof by batch or continuous processes. More particularly, this invention relates to making transparent soap bars and liquids which contain synthetic detergents, i.e. a "combo-bar".
2. Prior Art
Transparent soaps, and methods for their manufacture, have been well known and available for a great many years. Being costly to manufacture, they have been generally regarded as luxury items, and their properties have been equated with high purity and neutrality (although they may actually contain free alkali). Such products have been used almost exclusively in the toilet articles area, i.e. bathing, hand and face washing, etc.
Numerous transparent soaps have been formulated. A classic method involves the low temperature saponification of fats and oils predissolved in warm alcohol, water and glycerine, followed by evaporation of part of the alcohol/water azeotrope. Another common technique is based upon the addition of a polyhydric alcohol, such as glycerol, glycol, sugar or the like to a "neat soap" or semi-boiled soap, or to soap prepared by the cold process technique. Still another method consists of dissolving soap in alcohol to solubilize certain components and then distilling off most of the alcohol.
U.S. Pat. No. 3,562,167 to Kamen describes a transparent soap formed from a combination of soap, polyhydric alcohol and, as a surface-active agent, a polyalkoxy ether of an alkylphenol.
U.S. Pat. No. 3,903,008 to Deweever et al. describes the formulation of a transparent soap by the combination of soap, polyhydric alcohols and a quaternized dihydroimidazole detergent.
U.S. Pat. Nos. 3,793,214 and 3,926,828 to O'Neil et al. describe transparent soaps produced using branched chain fatty acids. U.S. Pat. No. 3,864,272 to Toma et al. describes the use of a rather complicated, elaborate mechanical method of working the soap, i.e. spray drying followed by mechanical working.
A method of formulating a transparent soap is disclosed in U.S. Pat. No. 2,820,768 where a sodium soap made from tallow, coconut oil and castor is mixed with a triethanolamine soap of stearic acid an oleic acid and an excess of the amine.
U.S. Pat. No. 4,290,904 describes a transparent low alkalinity bar soap based on a tetrakis (hydroxyalkyl) ethylene diamine.
Numerous other transparent soap bars are also known in the art, see, for example, Applicants' Information Disclosure filed herewith and incorporated herein by reference.
One of the disadvantages of these prior art transparent soap bars is that they form the typical scum in hard water. In order to overcome this problem with soaps in general, not only in transparent soaps, synthetic detergents were developed. It has been found, however, that when these synthetic detergents were added to the typical transparent soap to form what is called a "combo-bar" (i.e. a combination of synthetic detergent and soap), that the bar is no longer transparent. To the Inventors' knowledge, no one to date has made a transparent bar using a synthetic detergent and a soap having the enhanced transparency, clarity, color and purity of the soaps described and claimed herein nor has anyone used the solubilation system described and claimed herein for cosmetic ingredients.
Further, U.S. Pat. Nos. 4,278,655 and 4,293,544 to Elmi, and 4,275,222, 4,322,545, 4,323,693, and 4,323,694, to Scala, Jr., all assigned to Finetex, Inc., the Assignee herein, all described certain benzoic acid esters of primary alcohols of C.sub.9 to C.sub.18 carbon chain length. These esters are useful as diluents, solvents, plasticizers, liquid carriers, and the like, for cosmetic compositions. The entire disclosures of all of these patents are incorporated herein by reference.
Further, U.S. Pat. No. 3,741,911 to Shane describes certain alkyl-aryl polyoxyalkylene carboxylic acids and derivatives thereof for use as a surfactant in detergent compositions. The entire disclosure of this patent is incorporated herein by reference.
Applicant has discovered that when certain of these alkyl-aryl polyoxyalkylene carboxylic acids are utilized in conjunction with a combination of a synthetic detergent and a soap and, preferably, in conjunction with the aforementioned benzoic acid esters, that, surprisingly and unexpectedly, a truly transparent "combo-bar" is produced. Additionally, Applicants have also discovered that when these benzoic acid esters and alkyl-aryl polyoxyalkylene carboxylic acids are used, even without a synthetic detergent, these ingredients cause known transparent soap bars and liquids to have unexpected clarity. The combination may also be used as a solubilizer for cosmetic ingredients while maintaining clarity.